• Marked chainage
• Track survey and topographical detail
• OHLE heights and stagger
• Clearance profiles (clearoute sco file)
• Survey control points

However, tunnel surveys present their own specific problems and demand a specialist knowledge to arrive at valid solutions. We have extensive knowledge of working in tunnel environments and know how to coordinate survey stations effectively underground, maintain survey control against tamping, survey multiple clearoute sections, detail changes in construction and arrange the appropriate site access.

Tunnel surveys are also well suited to laser scanning. For example, in an irregular rock cutting, engineers may not know specifically where the main clearance problem areas are. Therefore the survey of cross sections would be an iterative affair, involving costly site re-visits. With Laser scanning, additional cross sections can be requested once the initial field work is completed: even requesting sections every half metre or less if required. Learn more….

Examples of relevant experience include:

• Severn Tunnel traverse and drainage survey
• Irregular bare rock tunnel for clearance surveys (Blaenau Ffestiniog)
• Thameslink tunnels
• Birmingham bridgeguard tunnel surveys
• Monitoring movement at Manton Tunnel and Birmingham New Street